The present disclosure relates to a cleaning device for cleaning an image carrier which carries a toner image, and an image carrier unit and an image forming apparatus having such a cleaning device.
Conventionally, as an image forming apparatus for forming an image on a sheet, known is technology of a sheet passing through a transfer nip part, which is formed between a photoreceptor drum and a transfer roller, in a direction from down to up. A toner image is formed on the photoreceptor drum, and the toner image is transferred to the sheet at the transfer nip part. The image forming apparatus further includes a fixing unit, and the sheet to which the toner image was transferred is subject to fixation processing by the fixing unit, and then discharged.
With the foregoing conventional technology, a cleaning device is disposed facing the photoreceptor drum in order to clean the residual toner on the photoreceptor drum after the toner image is transferred at the transfer nip part. As described above, when the sheet passes through the transfer nip part in a direction from down to up, the cleaning device that is disposed on the further downstream side in the rotating direction of the photoreceptor drum than the transfer nip part is often disposed above the photoreceptor drum.
When the cleaning member is disposed above the photoreceptor drum, there are cases where the residual toner that was removed from the photoreceptor drum falls from the periphery of the cleaning member. Thus, a toner seal member is disposed to come into contact with the photoreceptor drum around the cleaning member in order to prevent the residual toner from falling. Nevertheless, when a large amount of toner is accumulated above the toner seal member, such toner will press the toner seal member toward the photoreceptor drum. Thus, the contact pressure of the toner seal member against the photoreceptor drum will increase. Meanwhile, when paper dust of the sheet becomes attached to the cylindrical face of the photoreceptor drum at the transfer nip part, there are cases where the paper dust is moved to the leading end of the toner seal member in response to the rotation of the photoreceptor drum. When the contact pressure of the toner seal member against the photoreceptor drum is high as described above, the paper dust becomes a clump between the leading end of the toner seal member and the cylindrical face of the photoreceptor drum. Consequently, there are cases where the leading end of the toner seal member lifts due to the clump of the paper dust, and cause defects such as toner leakage.